[HDThoreaun]

brokers lend cash sitting in accounts.

[toomuchtodo]

Brokers only lend out of specific core cash accounts (FCASH at Fidelity, for example). Whether you hold cash in those account types is your choice, it isn’t mandatory.

https://www.fidelity.com/mutual-funds/fidelity-funds/money-m...

[kccqzy]

Can they lend treasuries sitting in accounts, if you don't have a margin account?

[HDThoreaun]

No, but treasuries lose value if interest rates increase.

[kccqzy]

Then hold short term treasuries. Problem solved.